The idea of putting economic pressure on a company instead of striking marks a twist in major U.S. unions` post-industrial bargaining strategies.

When American Telephone & Telegraph Co.`s contract expired Sunday with the Communications Workers and the International Brotherhood of Electrical Workers, AT&T predicted a strike would have little effect on services.

The company, the nation`s leading long-distance carrier and world`s largest telecommuncations firm, said it would rely on management, retirees and temporary workers during a strike.

Explaining their strategy, CWA officials said they would urge AT&T customers to shift their business to other long-distance carriers as part of a global campaign to pressure the telecommunications giant.

``The electronic picket line allows us to put even greater economic pressure on AT&T than if we had decided to go on strike last Saturday,`` said CWA president Morton Bahr.

With the labor movement`s backing of the strategy, he said the firm could lose as much as $5 million a week.

``I find it very difficult to understand,`` remarked AT&T Vice President William Ketchum, who said such an effort would hurt employees as well as the company.

Not only are most of its competitors non-union, but AT&T could not guarantee workers` job security if the effort hurts its business, he said.

The two unions have lost about 96,000 AT&T jobs since 1984 and want the company to guarantee them access to new jobs in the firm as well as a limit on jobs transferred to non-union ranks.

AT&T says it needs a contract that permits it to face new competitors in the U.S. and overseas.